Two seismic gaps on the Sagaing Fault, Myanmar, derived from relocation of historical earthquakes since 1918

摘要

Relocation of six M (magnitude) ≥7.0 earthquakes near the Sagaing Fault in Myanmar since 1918 allows us to image earthquake history along the Sagaing Fault. All the earthquakes were relocated on the Sagaing Fault by using the modified joint hypocenter determination method. Combining the relocated epicenters with information on foreshocks, aftershocks, seismic intensities, and coseismic displacement, we estimated the location of the fault plane that ruptured during each earthquake. This analysis revealed two seismic gaps: one between 19.2° N and 21.5°N in central Myanmar, and another south of 16.6°N in the Andaman Sea. Considering the length of the first seismic gap (～260 km), a future earthquake of up to M ～7.9 is expected to occur in central Myanmar. Because Nay Pyi Taw, the recently established capital of Myanmar, is located on the expected fault, its large population is exposed to a significant earthquake hazard.